This invention relates to a calorimeter.
A typical calorimeter includes a combustion vessel, also referred to as a bomb, in which a sample of a material is combusted, usually in a high pressure oxygen environment, to obtain data on the calorific characteristics of the material. The bomb may be immersed in a circulating liquid, e.g. water, and measurements of an increase in temperature of the liquid, resulting from combustion of the sample, are used to calculate the calorific value of the material.
Different materials combust in different ways depending for example on the presence or absence of inflammable volatile constituents. It is at least for this reason that a water-immersion calorimeter has found favor for the heat from the sample is totally absorbed in the water irrespective of the shape of a flame generated by the combusting material.
The use of a manually operated, water-immersion calorimeter is labor intensive for the quantity of water in which the bomb is immersed must be accurately dispensed for each test. Automated calorimeters have been developed to address this aspect. Although successful, such calorimeters are of complex construction and thus expensive.
One type of dry calorimeter which has been developed to eliminate the use of water includes a heat-conductive jacket which surrounds the combustion vessel and temperature sensors positioned at an interface between the jacket and the combustion vessel. Despite the heat dispersive effect of the conductive jacket it is possible for this type of calorimeter to produce deviant results for varying flame patterns, which are produced by combusting samples of materials with different properties, can result in temperature changes which are manifested differently in various parts of the bomb. The measurements of such temperatures are then dependent on the physical positions of the sensors.
High internal pressures are generated inside a bomb upon combustion of a sample. If an attempt is made to remove a lid of the bomb before the internal pressure is reduced the force which is exerted on the lid by the pressurized gas can violently project the lid from the bomb with the possibility of serious injury to an operator.
It is an object of the present invention to provide a calorimeter which, at least partly, addresses the aforementioned aspects.